Amja^ri8^9 -arir' }         Tests  for  Carbolic  Acid,  etc.  31 
volumes  the  liquid  remains  clear,  but  is  precipitated  by  8  volumes  of 
water.  Carbolic  acid  is  also  soluble  in  2  measures  of  9  per  cent,  soda, 
and  is  not  precipitated  by  less  excess  of  the  reagent  than  5  or  6 
measures.  Absolute  cresylic  acid  is  soluble  in  an  equal  measure  of  9 
per  cent,  soda,  but  is  precipitated  when  the  proportion  of  the  reagent 
is  increased  to  3J  volumes.  If  to  a  clear  mixture  of  equal  volumes  of 
cresylic  acid  and  9  per  cent,  soda,  a  few  drops  of  water  be  added,  pre- 
cipitation occurs,  and  when  the  proportion  of  water  is  increased  to  one 
volume,  the  orginal  bulk  of  cresylic  acid  separates  out.  Hence, 
cresylic  acid  is  insoluble  in  two  measures  of  4J  per  cent,  soda  solution. 
Creasote  is  insoluble  in  any  smaller  quantity  than  two  volumes  of  9 
per  cent.  soda.  It  is  partially  reprecipitated  when  the  proportion  of 
the  solvent  is  increased  to  more  than  three  and  half  measures. 
5.  Solubility  at  I5'5°C.  in  solution  of  Ammonia  (sp.  gr.  '88o) —Car- 
bolic acid  is  completely  and  readily  soluble  in  an  equal  volume  of 
strong  ammonia.  The  solution  is  not  precipitated  by  addition  of  less 
than  one  and  half  volume  of  water.  A  mixture  pf  one  part  of  car- 
bolic acid  and  three  of  cresylic  acid  is  soluble  in  an  equal  measure  of 
ammonia,  but  the  solution  is  precipitated  on  adding  even  a  few  drops 
of  water. 
6.  Behavior  with  Benzol. — Absolute  carbolic  and  cresylic  acid  and 
creasote  are  miscible  with  benzol  in  all  proportions. 
The  hydrous  substances  dissolve  in  five  volumes  of  benzol  with 
complete  separation  of  the  water.  Hence  benzol  may  be  used  for  the 
determination  of  the  proportion  of  water  present  in  samples  of  carbolic 
and  cresylic  acid. 
7.  With  Chloroform,  Carbon  Disulphide,  or  Ether. — Carbolic  acid, 
cresylic  acid,  and  creasote  react  in  much  the  same  manner  as  with 
benzol.  Agitation  with  9  per  cent,  soda  removes  them  from  their 
solutions  in  the  above  solvents. 
8.  Behavior  with  Petroleum  Spirit  of  sp.  gr.  '66g  [Commercial  "  Benzo- 
I'me  "). — Absolute  carbolic  acid  dissolves  half  its  volume  of  petroleum 
spirit,  forming  a  clear  liquid.  On  addition  of  a  larger  proportion  of 
petroleum  spirit  precipitation  occurs. 
With  one  volume  of  carbolic  acid  and  three  of  petroleum  spirit  the 
layers  have  about  the  same  measures  as  the  original  liquid.  Each 
layer,  however,  contains  both  liquids,  as  may  be  proved  by  cooling  the 
